MPLS vs IP

 It provides links to difference between circuit switching, packet switching and message switching.

Label switching uses labels instead of IP addresses for switching and routing the packets. It works at Layer 2.5 which resides between layer 2 (data link layer) and layer 3 (network layer).

MPLS Label Switching

There are three basic operations used in MPLS label switching. These operations are Push, Swap and Pop. At the start, push operation is used as ingress CE router assigns label to the packet. In between across LSPs (Label Switching Paths), swap operation is used. At the end, pop operation is used to take out label from the packet as it is no longer needed as destination has been arrived or reached.

Router Designation	Incoming Label	Incoming Interface	Destination network	Outgoing interface	Outgoing Label
R1	-	e0	172.16.1	S1	6
R2	6	S0	172.16.1	S2	11
R3	11	S0	172.16.1	S3	7
R4	7	S1	172.16.1	e0	-

Benefits or Advantages of MPLS Label Switching

Following are the benefits of MPLS Label Switching: 
• MPLS forwards any data across network. It is not based on destination IP address but it is based on tags or labels. 
• It can be used to transport any types of protocols e.g. ATM, SONET, Ethernet etc. 
• Both voice and data can be transported on same network.
• It uses bandwidth very effectively.
• It is network resilient with MPLS fast re-route feature.

MPLS Label Switching	IP Packet switching
Routes packet based on 20 bit label.	Routes packet based on 32 bit IP address
Established dedicated path known as LSP (Label Switching Path) before data flow.	Do not establish dedicated path , just transmit data gram which will be routed based on IP addresses.
Each router builds LFIB (Label Forwarding Information Base) table using LDP protocol.	Stores IP routing table.

Circuit Switching

In circuit switching network dedicated channel has to be established before the call is made between users. The channel is reserved between the users till the connection is active. For half duplex communication, one channel is allocated and for full duplex communication, two channels are allocated. It is mainly used for voice communication requiring real time services without any much delay. 

Packet Switching

In packet switching network unlike CS network, it is not required to establish the connection initially. The connection/channel is available to use by many users. But when capacity or number of users increases then it will lead to congestion in the network. Packet switched networks are mainly used for data and voice applications requiring non-real time scenarios. 

Circuit Switching	Packet Switching(Datagram type)	Packet Switching(Virtual Circuit type)
Dedicated path	No Dedicated path	No Dedicated path
Path is established for entire conversation	Route is established for each packet	Route is established for entire conversation
Call setup delay	packet transmission delay	call setup delay as well as packet transmission delay
Overload may block call setup	Overload increases packet delay	Overload may block call setup and increases packet delay
Fixed bandwidth	Dynamic bandwidth	Dynamic bandwidth
No overhead bits after call setup	overhead bits in each packet	overhead bits in each packet

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A virtual private network (VPN) is useful when you wish to create a secure connection between a client and a private network, over the public Internet.

 For example, a VPN can connect your laptop back to a company network, or it can connect two company offices. Each IP packet to be sent through the VPN connection (often called a tunnel) is encrypted and encapsulated inside anotherIP packet. This outside IP packet uses the source and destination address of the two end-points of the VPN tunnel, which are usually different than the addresses of the inside IP packet.

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Multiprotocol Label Switching (MPLS) is useful to steer or "switch" traffic in service provider backbones using tags or "labels.

One key application for MPLS is switching traffic for a large enterprise across the service provider backbone, where the labels keep the traffic distinct from other enterprises'. This use case is comparable to the inter-office encrypted tunnels described above, and thus is referred to as MPLS VPN. It's also comparable to traditional leased lines, which it often replaces. Because MPLS VPN requires the service provider to set up the labels in their network, they charge extra for it, along with other services like managing CPE at each office.